The present invention relates to internal combustion engines, and, more specifically, it is a device to vary the position and angular speed of a camshaft of an internal combustion engine.
A classical internal combustion engine includes an engine block, a plurality of reciprocating pistons that move alternatively inside the cylinders, a crankshaft coupled to the pistons in order to be rotated by the alternating movement of said pistons and a camshaft moved by the crankshaft through either a chain drive or belt drive. As the camshaft rotates, the cam lobe profile, fixed to the camshaft by cam lobes, pushes the intake valves or exhaust valves, causing the valves to open. After the cam lobe profile ceases to operate, it allows springs to return the valves to closed position. The design of the cam lobes and the position determines, among other things, the length of time the valves are held open.
In a standard four stroke engine, a cycle of operation (intake, compression, power and exhaust) takes place over four strokes of the piston, made in two crankshaft revolutions. When a piston is at the top of the cylinder at the beginning of the intake stroke, the intake valve opens and the descending piston draws in the air-fuel mixture. At the bottom of the stroke, the intake valve closes and the piston starts upward on the compression stroke. Just before or as the piston reaches the top again, the compressed air-fuel mixture is ignited by the firing of a spark plug, forcing the piston down on its power stroke. As the piston reaches the bottom of its stroke, the exhaust valve opens, allowing combustion products to be forced out through the exhaust valve.
Some internal combustion engines use dual camshaft, one to operate the intake valves (admission) and the other to operate the exhaust valves. Both camshafts in a dual camshaft engine can be driven by a chain drive or belt drive.
The performance of an internal combustion engine can be improved by changing the positional relationship of the camshaft relative to the crankshaft. For example, the camshaft can be retarded or delayed closing the intakes valves. In a dual camshaft engine, retarding or advancing the camshaft can be accomplished by changing the positional relationship of one of the camshaft, usually the camshaft that operates the intakes valves of the engine, relative to the other camshaft and the crankshaft. Retarding or advancing the camshaft varies the timing of the engine in terms of the operation of the intake valves relative to the exhaust valves, or in terms of the operation of the valves relative to the position of the crankshaft. This is achieved by the device, which is my property, the U.S. Pat. No. 6,640,760.
On the other hand the performance of an internal combustion engine can be improved if the intake valve is able to stay open longer during the intake stroke, to allow a greater quantity of air-fuel mixture to enter. Therefore the performance of an internal combustion engine can be improved in both ways:                1. Changing the position of the camshaft in relation to the crankshaft or changing the normal position of the intake camshaft in relation to the exhaust camshaft and the crankshaft (function already achieved in the U.S. Pat. No. 6,640,760) and        2. keeping the intake valve opened longer to allow a greater quantity of air-fuel mixture to enter in to the piston.        